Functions for kernel smoothing for Wand & Jones (1995)
S original by Matt Wand.
R port by  Brian Ripley <ripley@stats.ox.ac.uk>.
functions for kernel smoothing (and density estimation)
corresponding to the book:
Wand, M.P. and Jones, M.C. (1995) "Kernel Smoothing".
Unlimited use and distribution (see LICENCE).